Outline the sequence for commissioning a new installation from documentation to energisation.

• A. Start energising first, then perform visual checks
• B. Review drawings/specs; visual and clearance checks; insulation resistance test; continuity and earth continuity tests; verify protective device settings; energise
• C. Verify protective device settings first; perform functional tests; obtain sign-off; energise
• D. Review drawings/specs; visual and clearance checks; insulation resistance test; continuity and earth continuity tests; verify protective device settings; perform functional tests; obtain sign-off; energise

Answer: (D)

The main idea here is to follow a safe, thorough, and verifiable process that proves the installation is ready before power is applied. The commissioning sequence should verify design intent, physical condition, electrical integrity, protection settings, and actual operation, then obtain formal approval before energisation.

Starting with the documentation review ensures you’re checking against the approved drawings and specifications, so every part of the installation matches the design. Visual and clearance checks confirm that the layout is correct, components are properly installed, and there’s adequate access and clearance for safe operation and future maintenance. Next, insulation resistance testing assesses the health of insulation and helps detect moisture, damage, or contaminants that could cause leakage or short circuits once energized. Conducting continuity and earth continuity tests verifies that conductors form complete circuits where required and that a solid low-impedance path to earth exists for protective measures.

Verifying protective device settings is crucial to ensure each circuit will trip or operate as intended under fault conditions, and that protection coordination won’t result in unnecessary or unsafe trips. Functional tests then confirm that equipment, controls, interlocks, alarms, and interconnections behave correctly under simulated operating conditions, not just in theory. Obtaining sign-off brings in responsible parties to confirm all checks are complete and satisfactory, providing a formal go-ahead for energisation.

Finally, energisation completes the process, but only after all prior steps have established safety, compliance, and correct operation. The other sequences either skip essential checks or move to energisation too early, which could miss latent safety or performance issues.